Influenza del comportamento ciclico dei collegamenti trave-colonna sulla risposta sismica di telai in acciaio regolari - INFLUENCE OF THE CYCLIC BEHAVIOUR OF BEAM-TO-COLUMN CONNECTION ON THE SEISMIC RESPONSE OF REGULAR STEEL FRAMES Rosario Montuori, Elide Nastri, Vincenzo Piluso, Marina Troisi

The work presented is aimed at the investigation of the influence of beam-to-column connection typologies on the seismic response of regular and irregular MR-Frames designed according to the Theory of Plastic Mechanism Control (TPMC). The investigated typologies are four partial strength connections whose structural detail has been designed in order to obtain the same flexural resistance. The first three joints are designed by means of hierarchy criteria based on the component approach and are characterized by different location of the weakest joint component, leading to different values of joint rotational stiffness and plastic rotation supply and affecting the shape of the hysteresis loops governing the dissipative capacity. The last typology is a beam-to-column connection equipped with friction pads properly designed to assure the earthquake input energy dissipation. An appropriate modelling of structures is needed to accurately represent both strength and deformation characteristics, especially with reference to partial-strength connections where the dissipation of the earthquake input energy occurs. Beam-to-column joints are modelled by means of rotational inelastic spring elements located at the ends of the beams whose moment-rotation curve is characterized by a cyclic behaviour accounting for stiffness and strength degradation and pinching phenomenon. The parameters characterizing the joints cyclic hysteretic behaviour have been calibrated on the base of experimental results aiming to the best fitting. Successively, the prediction of the structural response of a MR-Frames equipped with such connections has been carried out by means of IDA analyses